Rh(III)-Catalyzed Synthesis of Substituted Isoindoles through a Direct C–H Activation/[4 + 1] Annulation and Acyl Migration Cascade of Oxadiazolones with Diazo Compounds

Abstract

A Rh(III)-catalyzed C–H bond activation for the synthesis of fused 2H-isoindole scaffolds from oxadiazolones with diazo compounds was developed. The reaction proceeded through C–H activation of oxadiazolones/[4 + 1] annulation, intramolecular cyclization, and an unusual acyl migration cascade to afford target scaffolds with good yields. These 2H-isoindole derivatives could be further transformed into intriguing drug privileged scaffolds.

Straightforward Access to Isoindoles and 1,2-Dihydrophthalazines Enabled by a Gold-Catalyzed Three-Component Reaction

“…Traditional methods enclose condensations, oxidation from isoindolines, reduction from isoindolinones, and cycloaddition or cycloreversion reactions . More recently, attractive transition-metal-catalyzed transformations have appeared, such as gold and silver cyclization over alkynes, gold [1,5]–H shift isomerizations, and C–H activations with rhodium carbenes . However, these methods often require not readily available starting materials or involve harsh conditions.…”

Rh(iii)-catalyzed C(sp2)–H functionalization/[4+2] annulation of oxadiazolones with iodonium ylides to access diverse fused-isoquinolines and fused-pyridines

“…Since Zhu et al reported a cyclization of 3-aryl-1,2,4-oxadiazolones with internal alkynes as coupling partners, allowing the synthesis of aminoisoquinolines in 2016, 9 these substrates have become important building blocks to construct substituted polyheterocycles. For instance, Rh( iii )-catalyzed oxadiazolone-directed alkenyl C–H activation/annulation with multiple types of alkynes, 10 vinylene carbonate, 11 and α-diazo carbonyl, 12 have been reported. Despite these achievements, the applications in constructing structurally diverse polyheterocycles are still in their infancy.…”